5. potential for human exposure 5.1 overview · 5.3.2 transformation and degradation 5.3.2.1 air...

DI-n-OCTYLPHTHALATE 75

5 POTENTIAL FOR HUMAN EXPOSURE

51 OVERVIEW

Di-n-octylphthalate is released mainly to the atmosphere and to some extent to surface waters in

industrial effluents (TRI92 1994) The compound may be released to soils in the disposal of plastics

wastes Di-n-octylphthalate is expected to partition mainly to soils and sediment upon release to the

environment (EPA 1979 1992c) The compound is also bioconcentrated by aquatic organisms

although biomagnification in aquatic food chains is not expected to be significant (EPA 1992d)

Aerobic biodegradation is the most important transformation process in soils and surface waters (EPA

1992a 1992c) Other transformation processes include photooxidation in the atmosphere and

photolysis in surface waters (EPA 1992a) As a result of confusion with its branched isomer di(2shy

ethylhexyl)phthalate limited unambiguous monitoring data are available for di-n-octylphthalate The

compound has been detected in ambient air rain runoff groundwater surface water and sediment

Human exposure to the compound is expected to occur primarily in workplace settings (HSDB 1995)

General population exposure pathways include inhalation of the volatilized plasticizer ingestion of

foods contaminated as a result of leaching of di-n-octylphthalate from plastic containers ingestion of

aquatic organisms that have bioconcentrated the compound and ingestion of contaminated drinking

water (EPA 1992c) Populations living near hazardous waste sites contaminated with di-n-octylphthalate

may also be exposed through dermal contact with and ingestion of contaminated

groundwater and sediments (ATSDR 1988 1989b 1989c) Populations with potentially high

exposures to di-n-octylphthalate include workers in the chemical manufacturing and plastics

manufacturing and processing industries individuals requiring routine medical care such as blood

transfusions and kidney dialysis treatments and individuals living in the vicinity of industrial

manufacturing and processing facilities that may manufacture or use di-n-octylphthalate or of

hazardous waste sites containing di-n-octylphthalate or plastics (HSDB 1995)

Di-n-octylphthalate has been identified in at least 300 of the 1416 hazardous waste sites on the EPA

National Priorities List (NPL) (HazDat 1995) However the number of sites evaluated for di-nshy

octylphthalate is not known The frequency of these sites within the United States can be seen in

DI-n-OCTYLPHTHALATE 76 5 POTENTIAL FOR HUMAN EXPOSURE

Figure 5-1 Of these sites 298 are located in the United States and 2 are located in the

Commonwealth of Puerto Rico (not shown)

52 RELEASES TO THE ENVIRONMENT

Considerable confusion exists in the literature about the TRI release reporting data and monitoring data

available for di-n-octylphthalate and its more common branched isomer di(2-ethylhexyl)phthalate

(EPA 1992a Vista Chemical 1992) The confusion exists because the terms ldquodioctyl phthalaterdquo and

ldquoDOPrdquo are often used as synonyms for di(2-ethylhexyl)phthalate which is the largest volume

plasticizer used in PVC Consequently some of the historical release and monitoring data reported in

the literature as ldquodioctyl phthalaterdquo and ldquoDOPrdquo refer to the more common branched isomer rather than

di-n-octylphthalate Therefore releases of di-n-octylphthalate and concentrations of the compound in

ambient media may actually be lower than historical data suggest Di-n-octylphthalate was withdrawn

from the TRI effective in 1993 (EPA 1995h) Thus the data for TRI92 (1994) is the most recent data

that is available from the Toxic Release Inventory for di-n-octylphthalate

521 Air

Di-n-octylphthalate may be released to the atmosphere through volatilization of the compound from

plastics as a result of manufacturing processes and through incineration (Vista Chemical 1992)

According to TR192 (1994) an estimated total of 15011 pounds of di-n-octylphthalate amounting to

about 98 of the total environmental release were discharged to the atmosphere from manufacturing

and processing facilities in the United States in 1992 (see Table 5-l) The TRI data listed in

Table 5-l should be used with caution since only certain types of facilities are required to report This

is not an exhaustive list Furthermore as noted above the precise chemical identity of the reported

releases is questionable

522 Water

Di-n-octylphthalate is released to surface waters in industrial waste waters from production and use

processes and as a result of spills during its transport storage and use (Mathur 1974a) For example

di-n-octylphthalate was found in one of five industrial process waste waters sampled at an average



concentration of 3700 microgL (EPA 1981) Releases to surface waters are expected to undergo

secondary treatment at publicly owned treatment works or at on-site National Pollutant Discharge

Elimination System (NPDES) permitted facilities Such waste-water treatment systems are expected to

remove 80-90 of the influent di-n-octylphthalate through a combination of adsorption and aerobic

biodegradation by acclimated microorganisms (EPA 1992c Petrasek et al 1983) The compound is

also released to surface waters from nonpoint sources such as surface runoff For example di-nshy

octylphthalate was found in runoff samples collected in 1982 from Little Rock Arkansas Bellevue

Washington and Eugene Oregon at a 4 frequency of detection in the collected samples and at

concentrations of 04-l microgL This sampling was conducted as part of the Nationwide Urban Runoff

Program (Cole et al 1984)

According to TR192 (1994) an estimated total of 41 pounds of di-n-octylphthalate were discharged to

surface waters from manufacturing and processing facilities in the United States in 1992 (see

Table 5-l) An estimated total additional 1475 pounds were transferred to publicly owned treatment

works The TRI data listed in Table 5-l should be used with caution since only certain types of

facilities are required to report This is not an exhaustive list Furthermore as noted above the

precise chemical identity of the reported releases is questionable

523 Soil


about 2 of the total environmental release was discharged to soils from manufacturing and

processing facilities in the United States in 1992 (see Table 5-l) An estimated total additional

239134 pounds were transferred to off-site waste treatment storage and disposal facilities The TRI

data listed in Table 5-l should be used with caution since only certain types of facilities are required

to report This is not an exhaustive list Furthermore as noted above the precise chemical identity of

the reported releases is questionable

DI-n-OCTYLPHTHALATE 82 5 POTENETIAL FOR HUMAN EXPOSURE

53 ENVIRONMENTAL FATE

531 Transport and Partitioning

Upon release to surface waters di-n-octylphthalate is expected to partition mainly to sediments and to

suspended particulates In a pilot-scale waste-water treatment system di-n-octylphthalate partitioned

mainly to primary treatment sludge (Petrasek et al 1983) The compound strongly adsorbs to organic

matter contained in soils and sediments adsorption is probably the most important transport process

for the compound in surface waters (EPA 1979 1992c) Volatilization from surface waters is expected

to be a slow and unimportant process For example the estimated volatilization half-life from a model

river 1 meter deep with a current of 1 metersecond and a wind speed of 3 meterssecond is 13 days

(HSDB 1995) In a pilot-scale study of a typical waste-water treatment plant employing both primary

and secondary activated sludge treatment processes no di-n-octylphthalate was lost from the system by

air stripping (Petrasek et al 1983) However in a study simulating the behavior of di-n-octylphthalate

in different aquatic systems volatilization was estimated to account for up to 20 of the losses of the

compound from certain standing surface water systems characterized by long water detention times

(eg ponds lakes) especially in relatively pristine lakes where loss by biodegradation is not likely to

be important (Wolfe et al 1980) This same study suggests that in running surface waters such as

rivers di-n-octylphthalate is most likely to be lost by transport out of the system

Di-n-octylphthalate also strongly adsorbs to soils and does not undergo leaching to groundwater as

indicated by its estimated soil organic carbonwater partition coefficient (Koc) of about 19000

Volatilization from soils is not expected to be significant (HSDB 1994 Vista Chemical 1992)

Di-n-octylphthalate released to the atmosphere may partition to soils and surface waters through wet

(Ligocki et al 1985) and dry (Vista Chemical 1992) deposition processes

Di-n-octylphthalate is bioconcentrated by aquatic organisms (EPA 1992d) In a 33-day combined

terrestrial-aquatic model ecosystem study the following di-n-octylphthalate bioconcentration factors

(BCFs) were reported (1) algae - 28500 (2) daphnids - 2600 (3) fish and mosquitoes - 9400 and

(4) snails - 13600 However the half-life for the disappearance of di-n-octylphthalate from this model

system was estimated to be about 5 days as the result of metabolism of the compound An EPA

(1992d) hazard assessment stated that although di-n-octylphthalate does bioconcentrate in aquatic


organisms the compound is not expected to biomagnify in aquatic food chains however this citation

did not contain and does not reference any studies that provide a basis for this conclusion In

greenhouse studies using radiolabeled di-n-octylphthalate added to soils the compound was not

bioconcentrated by crop plants (BCF lt1) (EPA 1986e) In a more recent screening study that

examined the potential of contaminants contained in sewage sludge to transfer into agricultural

products on the basis of their physicalchemical properties di-n-octylphthalate was judged to have a

high potential to adsorb to soil sludge solids and plant root surfaces and a low potential for leaching

uptake and translocation by plants and transfer to animal tissues by foliage ingestion (Wild and Jones

1992)

532 Transformation and Degradation

5321 Air

The most important transformation process for di-n-octylphthalate present in the atmosphere as an

aerosol is reaction with photochemically produced hydroxyl radicals The half-life for this reaction has

been estimated to be 45-448 hours (Howard et al 1991) Actual atmospheric half-lives may be

longer since phthalate esters sorbed to wind-entrained particulates may have long atmospheric

residence times (Vista Chemical 1992) Direct photolysis in the atmosphere is not expected to be an

important process (EPA 1993a HSDB 1995)

5322 Water

Phthalate esters undergo a step-wise alkaline hydrolysis to monoesters and then to dicarboxylic acids

As a result of the relatively slow rates of this reaction at pH 6-9 and the low water solubility of di-nshy

octylphthalate chemical hydrolysis of the compound is not an environmentally important

transformation process (EPA 1992a) Hydrolytic half-lives at 25degC and pH 7 and 9 have been

estimated to be 107 and 7 years respectively (Howard et al 1991)

Biodegradation is the primary process by which phthalate esters are removed from surface waters

rates are strongly dependent on acclimation of microbial communities (EPA 1992a 1992~) Wolfe et

al (1980) predicted that biodegradation would be the most important mechanism by which di-nshy

octylphthalate would be removed from eutrophic lakes In static culture flask biodegradation screening


tests about 93-94 of di-n-octylphthalate was metabolized after 3 weeks only after serial subculturing

of acclimated microorganisms (Tabak et al 1981) Enzymatic hydrolysis is the mechanism used by

microbes in the aerobic biotransformation of di-n-octylphthalate The ester is hydrolyzed to soluble

intermediates presumably via a pathway producing a phthalic acid monoester (EPA 1993a) however

data on the identity of biodegradation products were not available Aerobic biodegradation half-lives

range from 1 to 4 weeks in surface waters and from 2 weeks to 1 year in groundwater (Howard et al

1991) Biodegradation under anaerobic conditions occurs at a slower rate (EPA 1993a) it has been

predicted that di-n-octylphthalate will accumulate in natural sediments because it is persistent under

anaerobic conditions (EPA 1992d) For example in anaerobic digester studies using diluted and

undiluted sewage treatment plant sludge between 40 and 75 of di-n-octylphthalate remained

undegraded after a 10-week incubation period (Shelton et al 1984) Anaerobic half-lives for aquatic

systems have been predicted to range from 6 months to 1 year (Howard et al 1991)

Di-n-octylphthalate may also undergo photolysis in surface waters as a result of its absorption of

electromagnetic radiation at wavelengths less than 290 nm The estimated photolytic half-life of the

compound in surface water is 144 days (EPA 1992a) Photolysis was predicted to be the most

important removal mechanism after volatilization for di-n-octylphthalate losses from oligotrophic lakes

(Wolfe et al 1980)

5323 Sediment and Soil

As discussed above aerobic biotransformation is expected to be the most important process in the

removal of di-n-octylphthalate from soils anaerobic biodegradation occurs in sediments (EPA 1992a)

However because of its persistence under anaerobic conditions di-n-octylphthalate is expected to

accumulate in sediments (EPA 1992d) Di-n-octylphthalate has been reported to undergo

biodegradation by a variety of acclimated soil microorganisms (HSDB 1995 Mathur 1974b) however

data on the identity of biodegradation products were not located

54 LEVELS MONITORED OR ESTIMATED IN THE ENVIRONMENT

As previously discussed considerable confusion exists in the literature about the monitoring data

available for di-n-octylphthalate and di(2-ethylhexyl)phthalate Only monitoring data that clearly


concerned di-n-octylphthalate were included in this section of the profile data from ambiguous studies

were not included

541 Air

Di-n-octylphthalate was detected in five of seven ambient air and six of seven rainwater samples

collected during rain events that occurred in February through April 1984 in Portland Oregon Di-nshy

octylphthalate concentrations ranged from 26 to 20 ngL in rain samples and from 006 to 094 ngm3

in air samples (Ligocki et al 1985)

542 Water

Di-n-octylphthalate was detected in 4 of the urban runoff samples collected from a total of 15 cities

Di-n-octylphthalate was detected at three cities at concentrations of 04-l microgL (Cole et al 1984) The

compound was found in water samples collected at four locations along the entire length of the

Mississippi River at concentrations of 24-310 ngL (DeLeon et al 1986) At the Butler Mine Tunnel

NPL Site located in Pittston Pennsylvania di-n-octylphthalate was detected in on-site oilgroundwater

samples at concentrations of ll0-792000 ppb (ATSDR 1989b) Di-n-octylphthalate was detected at a

concentration of 1 ppb in a water sample collected from the discharge pond of a phthalate ester plant

located on the Chester River in Maryland (Peterson and Freeman 1984) Di-n-octylphthalate was

found at 0001-002 ppm in water samples taken from a river that received industrial waste water from

a specialty chemical manufacturing plant (Jungclaus et al 1978)

Estimates of di-n-octylphthalate concentrations in receiving waters located downstream from two plants

reporting releases of the compound to the TRI have been developed by EPA (1992c) Mean flow

concentrations of about 3-9 microgL and 7-year Ql0 low-flow concentrations of about 90-390 microgL were

estimated for the surface waters receiving effluent from the on-site treatment facility used at one plant

and the publicly owned treatment facility that handles the effluent from the other plant

Concentrations of di-n-octylphthalate in drinking water utility influents have been estimated to be less

than 05 ppb (EPA 1992c)



In the sediment of a discharge pond of a phthalate ester plant located on the Chester River in

Maryland di-n-octylphthalate was detected at a concentration of 12000 ppb In sediment samples

from the Chester River taken 2 km and 8 km downstream from the plant the compound was found at

concentrations of 62 and lt5 ppb respectively (Peterson and Freeman 1984) In the sediment of a

river that received industrial waste water from a specialty chemical manufacturing plant di-nshy

octylphthalate was detected at concentrations ranging from 15 to 25 ppm (Jungclaus et al 1978) At

the Dixie Caverns Landfill NPL site located in Salem Virginia di-n-octylphthalate was detected on-site at

a concentration of 80 ppm (ATSDR 1988) however the media in which this concentration was

detected was not specified Off-site sediment samples collected at the Revere Chemical Company

NPL site located in Revere Pennsylvania were found to contain 2300 ppb di-n-octylphthalate

(ATSDR 1989c)

EPA (1992c) developed estimates of di-n-octylphthalate concentrations in the sediments of surface

waters located downstream from two plants reporting releases of the compound to the TRI The

surface waters received effluents from an on-site treatment facility and a publicly owned treatment

facility Steady-state sediment concentrations were estimated to exceed 10 mgkg and possibly

gt50 mgkg downstream from the two facilities

544 Other Environmental Media

Di-n-octylphthalate is produced as a decomposition product of the pesticide dinocap (HSDB 1995)

55 GENERAL POPULATION AND OCCUPATIONAL EXPOSURE

Humans are expected to be exposed to di-n-octylphthalate mainly in the workplace (HSDB 1994)

The National Occupational Exposure Survey (NOES) conducted between 1981 and 1983 estimated

that 10393 workers (including 1434 women) in 1177 facilities were exposed to di-n-octylphthalate in

the workplace in 1980 (NIOSH 1993)

Exposure of the general population to di-n-octylphthalate may occur through ingestion of foods

contaminated by leaching of the compound from plastic containers transfusions of blood or other



fluids through medical tubing ingestion of aquatic organisms that have bioconcentrated the compound

and consumption of contaminated drinking water (EPA 1992c HSDB 1995) An additional potential

source of human exposure is contact with contaminated media at hazardous waste sites For example

di-n-octylphthalate has been detected in on-site sediment and groundwater samples and off-site

sediment samples collected at NPL hazardous waste sites The human exposure pathways of concern

at these sites include ingestion of contaminated groundwater and sediment (ATSDR 1988 1989b

1989c) Since data are not available on the dermal absorption of di-n-octylphthalate it is not known

whether dermal contact with di-n-octylphthalate at hazardous waste sites would represent an exposure

pathway of concern

In an early report of the 1982 annual results of the National Human Adipose Tissue Survey (NHATS)

a compound identified as di-n-octylphthalate was reportedly detected in 31 of the composite human

adipose tissue samples taken in the various regions of the United States that year Concentrations in

lipid ranged from below the level of detection (9 ngsample) to a maximum of 850 ngg (EPA 1986d)

However a later report of the 1982 results stated that the chemical detected was not di-n-octylphthalate

but was actually diethylhexyl phthalate (EPA 1989b)

56 POPULATIONS WITH POTENTIALLY HIGH EXPOSURES

Patients receiving regular dialysis on a kidney machine or receiving blood transfusions may be the

populations with the highest potential exposure to di-n-octylphthalate Workers in industries that

produce or use plastics especially materials processed at high temperatures are also expected to have

potentially high exposure to di-n-octylphthalate especially via inhalation of the volatilized plasticizer

Members of the general population living in the vicinity of industrial facilities that manufacture or

process the compound or plastic materials containing the compound as well as individuals living near

hazardous waste sites known to be contaminated with di-n-octylphthalate are also expected to have

potentially high exposures through contact with contaminated environmental media (HSDB 1995)

57 ADEQUACY OF THE DATABASE

Section 104(i)(5) of CERCLA as amended directs the Administrator of ATSDR (in consultation with

the Administrator of EPA and agencies and programs of the Public Health Service) to assess whether

adequate information on the health effects of di-n-octylphthalate is available Where adequate


information is not available ATSDR in conjunction with the NTP is required to assure the initiation

of a program of research designed to determine the health effects (and techniques for developing

methods to determine such health effects) of di-n-octylphthalate

The following categories of possible data needs have been identified by a joint team of scientists from

ATSDR NTP and EPA They are defined as substance-specific informational needs that if met would

reduce the uncertainties of human health assessment This definition should not be interpreted to mean

that all data needs discussed in this section must be filled In the future the identified data needs will

be evaluated and prioritized and a substance-specific research agenda will be proposed

571 Identification of Data Needs

Physical and Chemical Properties The physical and chemical properties of di-n-octylphthalate are

sufficiently well defined to allow assessments of the environmental fate of the

compound to be made Therefore no additional information is needed a this time

Production ImportExport Use Release and Disposal Because of the general

confusion in the literature about the nomenclature for octylphthalate esters historical information about

the production and importexport of di-n-octylphthalate is not readily available These values generally

must be estimated as a percentage of di(2-ethylhexyl)phthalate production or importexport The

compound is used principally as a plasticizer additive to plastics and PVC resins It is also used as a

dye carrier in plastics production and as a chemical intermediate (EPA 1993a HSDB 1995 Mannsville

Chemical Products Corporation 1989 Sittig 1991) Limited information is available about releases of

di-n-octylphthalate to environmental media Even the TRI data which comprise the most current

information available contain errors as a result of the nomenclature confusion (EPA 1993a Vista

Chemical 1992) Data are available about the disposal and regulatory status of the compound (see

Chapters 4 and 7) More information on the production and releases of di-n-octylphthalate is needed

to estimate potential exposure to the compound

According to the Emergency Planning and Community Right-to-Know Act of 1986 42 USC Section

11023 industries are required to submit substance release and off-site transfer information to the EPA

The Toxics Release Inventory (TRI) which contains this information for 1993 became available in

May of 1995 This database will be updated yearly and should provide a list of industrial production


facilities and emissions However di-n-octylphthalate was withdrawn from the TRI effective in 1993

(EPA 1995h)

Environmental Fate Di-n-octylphthalate partitions primarily to soils and sediment upon release to

the environment The compound is expected to be strongly sorbed to soil and sediment particulates

therefore it should have limited mobility (EPA 1979 1992c) Biodegradation half-lives of l-4 weeks

have been estimated for aerobic surface waters and soils Biodegradation also takes place in

sediments half-lives under anaerobic conditions have been estimated to range from of 6 months to

1 year (Howard et al 1991) The compound may also undergo photolysis in surface waters (estimated

half-life of 144 days) and photooxidation in the atmosphere (estimated half-life of about 5-45 hours)

(Howard et al 1991) Di-n-octylphthalate may persist in sediments as a result of its limited rate of

biotransformation and preferential partitioning to this medium

However although degradation is known to occur under both aerobic and anaerobic conditions data

are not available on the identity of degradation products Because the limited studies on the

mechanisms of injury from di-n-octylphthalate suggest that mono-n-octylphthalate is the proximate

toxicant it is important to know whether the reduction of di-n-octylphthalate is coupled with the

accumulation of mono-n-octylphthalate The environmental fate of di-n-octylphthalate and its

metabolites is not sufficiently understood to allow assessments of its exposure potential to be made

Additional data are needed on the identify and fate of degradation products of di-n-octylphthalate No

additional information is needed about the transport and partitioning of the compound at this time

Bioavailability from Environmental Media No information was found regarding the

absorption of di-n-octylphthalate by humans or laboratory animals following inhalation or dermal

exposures No information is available about absorption following oral exposure in humans However

indirect evidence from animal studies suggests that the compound is readily absorbed by this route (Albro

and Moore 1974 Oishi 1990) Additional information is needed on the absorption of di-n-octylphthalate

as a result of inhalation of contaminated air ingestion of contaminated food and water and dermal

contact with contaminated soils and sediments


Food Chain Bioaccumulation Di-n-octylphthalate bioconcentrates in aquatic organisms

However as a result of metabolism of the compound biomagnification in aquatic food chains does not

occur (EPA 1992d) It appears that the compound is not bioconcentrated by terrestrial plants or

animals or biomagnified in terrestrial food chains (EPA 1986e Wild and Jones 1992) However the

Wild and Jones (1992) study is limited to mathematical modeling results Thus only limited data are

available regarding the bioaccumulation and biomagnification of di-n-octylphthalate and the potential

for human exposure resulting from the bioaccumulation of the compound is not well understood

Therefore additional data are needed to validate the Wild and Jones (1992) model Also an

estimation of animal uptake from soil ingestion is needed to support this study

Exposure Levels in Environmental Media Reliable monitoring data for the levels of di-nshy

octylphthalate in contaminated media at hazardous waste sites are needed so that the information

obtained on levels of di-n-octylphthalate in the environment can be used in combination with the

known body burden of di-n-octylphthalate to assess the potential risk of adverse health effects in

populations living in the vicinity of hazardous waste sites Di-n-octylphthalate has been detected in

ambient air rain surface water groundwater and sediment However as a result of the confusion

about the nomenclature for octylphthalate esters much of the historical monitoring data available

actually pertain to the branched isomer di(2-ethylhexyl)phthalate (Vista Chemical 1992) Therefore

little current information specific to the n-octyl isomer is available regarding concentrations of the

compound in foods drinking water and environmental media particularly with respect to media at

hazardous waste sites The lack of monitoring data precludes the estimation of human exposure via

intake of or contact with contaminated media

Exposure Levels in Humans This information is necessary for assessing the need to conduct

health studies on these populations Di-n-octylphthalate has historically been reported to have been

found in human adipose tissue (EPA 1986d) However more recent information indicates that the

compound detected was actually the branched di(Zethylhexy1) isomer (EPA 1989b) Additional

information on the concentrations of di-n-octylphthalate in human tissues and fluids parficularly for

populations living near hazardous waste sites is needed to assess potential human exposure to the

compound


Exposure Registries No exposure registries for di-n-octylphthalate were located This substance

is not currently one of the compounds for which a subregistry has been established in the National

Exposure Registry The substance will be considered in the future when chemical selection is made

for subregistries to be established The information that is amassed in the National Exposure Registry

facilitates the epidemiological research needed to assess adverse health outcomes that may be related

to exposure to this substance

572 On-going Studies

No information was found in the available literature concerning on-going studies dealing with the

environmental fate or human exposure potential of di-n-octylphthalate


Figure 5-1 Of these sites 298 are located in the United States and 2 are located in the

Commonwealth of Puerto Rico (not shown)

52 RELEASES TO THE ENVIRONMENT

Considerable confusion exists in the literature about the TRI release reporting data and monitoring data

available for di-n-octylphthalate and its more common branched isomer di(2-ethylhexyl)phthalate

(EPA 1992a Vista Chemical 1992) The confusion exists because the terms ldquodioctyl phthalaterdquo and

ldquoDOPrdquo are often used as synonyms for di(2-ethylhexyl)phthalate which is the largest volume

plasticizer used in PVC Consequently some of the historical release and monitoring data reported in

the literature as ldquodioctyl phthalaterdquo and ldquoDOPrdquo refer to the more common branched isomer rather than

di-n-octylphthalate Therefore releases of di-n-octylphthalate and concentrations of the compound in

ambient media may actually be lower than historical data suggest Di-n-octylphthalate was withdrawn

from the TRI effective in 1993 (EPA 1995h) Thus the data for TRI92 (1994) is the most recent data

that is available from the Toxic Release Inventory for di-n-octylphthalate

521 Air

Di-n-octylphthalate may be released to the atmosphere through volatilization of the compound from

plastics as a result of manufacturing processes and through incineration (Vista Chemical 1992)


about 98 of the total environmental release were discharged to the atmosphere from manufacturing

and processing facilities in the United States in 1992 (see Table 5-l) The TRI data listed in

Table 5-l should be used with caution since only certain types of facilities are required to report This

is not an exhaustive list Furthermore as noted above the precise chemical identity of the reported

releases is questionable

522 Water

Di-n-octylphthalate is released to surface waters in industrial waste waters from production and use

processes and as a result of spills during its transport storage and use (Mathur 1974a) For example

di-n-octylphthalate was found in one of five industrial process waste waters sampled at an average



















523 Soil














































1992)


5321 Air







5322 Water



























(Wolfe et al 1980)













were not included

541 Air





542 Water






























(ATSDR 1989c)

























pathway of concern



















































(EPA 1995h)





















































compound





























523 Soil














































1992)


5321 Air







5322 Water



























(Wolfe et al 1980)













were not included

541 Air





542 Water






























(ATSDR 1989c)

























pathway of concern



















































(EPA 1995h)





















































compound

















































1992)


5321 Air







5322 Water



























(Wolfe et al 1980)













were not included

541 Air





542 Water






























(ATSDR 1989c)

























pathway of concern



















































(EPA 1995h)





















































compound




























(Wolfe et al 1980)













were not included

541 Air





542 Water






























(ATSDR 1989c)

























pathway of concern



















































(EPA 1995h)





















































compound













were not included

541 Air





542 Water






























(ATSDR 1989c)

























pathway of concern



















































(EPA 1995h)





















































compound























(ATSDR 1989c)

























pathway of concern



















































(EPA 1995h)





















































compound





















pathway of concern



















































(EPA 1995h)





















































compound










































(EPA 1995h)





















































compound







































compound











5. potential for human exposure 5.1 overview · 5.3.2 transformation and degradation 5.3.2.1 air...

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